The British broadcaster engaged in a "serious breach" of broadcasting rules by failing to disclose that the voice of a documentary about the Gaza situation was the child of a Hamas representative, as ruled by UK media regulator Ofcom.
An probe by Ofcom into Gaza: How to Survive a Warzone has concluded that the documentary was "significantly deceptive".
The chief executive of the broadcaster had earlier expressed regret, stating there had been "a major oversight in relation to accuracy".
The authority has ordered the BBC to broadcast a prime-time declaration about its findings.
"As this represents a serious breach of our rules, we are directing the corporation to transmit a statement of our findings against it on BBC2 at 21:00, with a date to be finalised," the statement read.
'Risk to Erode Credibility'
The regulator's report stated: "Our investigation found that the programme's omission to reveal that the voice's parent held a position in the Hamas-administered government was significantly deceptive.
"It meant that the public did not have essential details which may have been highly relevant to their evaluation of the presenter and the information he presented.
"Confidence is at the core of the connection between a media organization and its audience, notably for a public service broadcaster such as the BBC.
"This error had the possibility to erode the exceptionally strong amounts of confidence that the public would have invested in a documentary produced by the BBC about the conflict in Gaza."
The documentary was withdrawn from the BBC's streaming service in February after the narrator's personal associations came to light, and in this past July an internal BBC review determined it infringed the corporation's editorial guidelines on accuracy.
A representative for the broadcaster commented: "The authority's determination is in agreement with the results of Peter Johnston's review, that there was a serious error in the film in relation to the corporation's content standards on accuracy, which reflects regulation 2.2 of the regulator's media standards.
"We have apologised for this and we comply with Ofcom's decision in full. We will follow the sanction as soon as the schedule and language are finalised."
